Date: Wed, 21 Jan 1998 15:39:04 -0800 (PST)
Message-Id: <199801212339.PAA05762@adit.ap.net>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
To: Eli Zaretskii <eliz AT is DOT elta DOT co DOT il>,
        Christopher Croughton <crough45 AT amc DOT de>
From: Nate Eldredge <eldredge AT ap DOT net>
Subject: Re: DJ port of GCC 2.8.0?
Cc: djgpp AT delorie DOT com
Precedence: bulk

At 04:01  1/21/1998 +0200, Eli Zaretskii wrote:
>
>On Wed, 21 Jan 1998, Christopher Croughton wrote:
>
>> Incidentally, why do you have to rebuild gcc with itself?  Is it just
>> to get the better optimisation, or is there some reason that building
>> it with the old version doesn't work properly?
>
>To get better code in GCC itself.  This includes better optimizations and 
>fewer bugs (because of bugs in code generation which are corrected in the 
>newer version).
>
>Don't forget that GCC is just another program.  So compiling it with a 
>(hopefully) better compiler makes it better.
Also to test it, if you want. One can build the compiler 3 times:

Stage 1: Compiled with previous compiler, to bootstrap.
Stage 2: Compiled with Stage 1, to get optimizations, etc.
Stage 3: Compiled with Stage 2. Stages 2 and 3 should have identical object
code.

This way, if the (Stage 2) compiler generates bad code, it will show up in
that the Stage 3 compiler will crash or itself generate different code.
That's the theory, anyway.

Nate Eldredge
eldredge AT ap DOT net